monitoring: Provide health hook

modules/monitoring/library/Monitoring/ProvidedHook/Health.php

@@ -0,0 +1,81 @@
+<?php
+/* Icinga Web 2 | (c) 2021 Icinga GmbH | GPLv2+ */
+
+namespace Icinga\Module\Monitoring\ProvidedHook;
+
+use Icinga\Application\Hook\HealthHook;
+use Icinga\Date\DateFormatter;
+use Icinga\Module\Monitoring\Backend;
+use ipl\Web\Url;
+
+class Health extends HealthHook
+{
+    /** @var object */
+    protected $programStatus;
+
+    public function getName()
+    {
+        return 'Icinga';
+    }
+
+    public function getUrl()
+    {
+        return Url::fromPath('monitoring/health/info');
+    }
+
+    public function checkHealth()
+    {
+        $backendName = Backend::instance()->getName();
+        $programStatus = $this->getProgramStatus();
+        if ($programStatus === false) {
+            $this->setState(self::STATE_UNKNOWN);
+            $this->setMessage(sprintf(t('%s is currently not up and running'), $backendName));
+            return;
+        }
+
+        if ($programStatus->is_currently_running) {
+            $this->setState(self::STATE_OK);
+            $this->setMessage(sprintf(
+                t(
+                    '%1$s has been up and running with PID %2$d %3$s',
+                    'Last format parameter represents the time running'
+                ),
+                $backendName,
+                $programStatus->process_id,
+                DateFormatter::timeSince($programStatus->program_start_time)
+            ));
+        } else {
+            $this->setState(self::STATE_CRITICAL);
+            $this->setMessage(sprintf(t('Backend %s is not running'), $backendName));
+        }
+
+        $this->setMetrics((array) $programStatus);
+    }
+
+    protected function getProgramStatus()
+    {
+        if ($this->programStatus === null) {
+            $this->programStatus = Backend::instance()->select()
+                ->from('programstatus', [
+                    'program_version',
+                    'status_update_time',
+                    'program_start_time',
+                    'program_end_time',
+                    'endpoint_name',
+                    'is_currently_running',
+                    'process_id',
+                    'last_command_check',
+                    'last_log_rotation',
+                    'notifications_enabled',
+                    'active_service_checks_enabled',
+                    'active_host_checks_enabled',
+                    'event_handlers_enabled',
+                    'flap_detection_enabled',
+                    'process_performance_data'
+                ])
+                ->fetchRow();
+        }
+
+        return $this->programStatus;
+    }
+}

modules/monitoring/run.php

@@ -4,4 +4,5 @@
 /** @var $this \Icinga\Application\Modules\Module */
 
 $this->provideHook('ApplicationState');
+$this->provideHook('Health');
 $this->provideHook('X509/Sni');